The debate about Scottish independence has been clattering away in the background for some time but with the vote now just six months away the noises off seem to have ratcheted up a level this week, transformed from a vague burble of hectoring anxieties into what can only be described as a slightly louder burble of hectoring anxieties.

Particularly striking was the news that David Cameron had let out "a little cry of joy" while watching David Bowie's acceptance message at the Brit awards last week, when the Thin White Duke lectured via his proxy an audience of cocaine-fuelled music industry hangers-on about the overriding cultural importance of Scotland remaining part of the historic union.

It is easy to picture the reaction to this in the prime ministerial quarters. The sudden cocking of the head. The rustle of monogrammed pyjama. The quivering upper lip. The single hank of hair falling across that clammy dome. And finally, in a reverie of snow-white alien pop god androgyny striding across the Tory blue re-election stage in spangled Tartan hot-pants, the little cry of joy, the retreat into moody silence, the half hour in the Chesterfield recliner listening to the Little Drummer Boy (feat Bing Crosby).

This is a very important issue and there are clearly plenty of English people who do feel a distinct cultural connection with Scotland – even a select class who tend to own large parts of it and see the Highlands in particular as a kind of rambling ancestral back garden tended by whisky-soaked tenant farmers. But for many southerners the relationship with Scotland is, out of a combination of ignorance and distance, often quite vague. It is a relationship that has in the last few decades been defined most obviously by sport; and above all – with all due apologies to everyone concerned – by football.

The Scotification of English football goes back right to the start of things, a beautifully fertile process so deeply ingrained it could be argued there has never actually been a purely English club game at any stage. Instead, pretty much every significant English club football triumph has had a Scottish tinge, from the early "Scotch Professors" who transformed the FA's primitive dribbler's blueprint into the combination game that is the basis of all modern football to the gaggles of ball-playing inside-forwards flushed from the Highland undergrowth by lasso-wielding speculator-agents to staff the newly booming southern leagues

Indeed in the past 25 years, the English top tier has been won 18 times by three different Scottish managers and just once by an Englishman. And yet this is a relationship where independence has already effectively been declared.

The disappearance of Scottish players and – yes, they're coming for you too – Scottish managers from England's top division is one of the unremarked slow-motion footballing tragedies of the past 20 years. This week the current round of Champions League ties passed its midway point with four English clubs involved and just one Scottish player, Darren Fletcher, available to them. This in itself seems poignant given the gloriously defining role Scotsmen have played in so many of English club football's best moments overseas.

The years when English clubs dominated the old European Cup were essentially an Anglo‑Scottish pact of iron, with at least three Scots in each of the Liverpool, Nottingham Forest and Aston Villa teams that won it six seasons out of eight between 1978 and 1984. This was the real golden age of the Anglo-Scots club game, a period when not only did Scotland produce the only genuinely brilliant football film ever made (Gregory's Girl, naturally) but tough, inventive, alluringly distinctive Scottish footballers just seemed to fall from the skies like ripe autumn fruit.

There was a majesty to that generation of tight‑shorted, skinny-legged Scots, a marriage of wiry power and grace in a player such as Alan Hansen, who didn't really look like a footballer at all but resembled instead some baleful, sardonic long-striding, new-romantic android warrior.

There were brilliant Scots everywhere, from Archie Gemmill, a small, galloping nodule of footballing gristle; to the mooching, dreamy Steve Archibald, who carried with him the air of a languid and cosseted sixth form poet; to Graeme Souness, the best kind of surprisingly sensitive terrifyingly angry hard man, the kind of surprisingly sensitive terrifyingly angry hard man who looks like he might insist on sitting you down and explaining exactly why it's necessary to stamp his great thick stumpy little hatchet-man's boot down on your ankle, doing it so eloquently and persuasively and with so many thrillingly enjoyable finger-stabs to the solar plexus that by the end you're practically begging him to get on with it.

And yet somehow all this fine-point talent has disappeared. By all accounts the problems in Scottish football are pretty much the same as those facing English football, just on a more annihilating scale: wider societal habits, lack of resources, clubs who buy in rather than train up, and a cycle of apparently irreversible hierarchical waste. In the end Scotland's decline just looks like another part of the wider falling away of the traditional northern European game, a concussive, mud-bound kind of footballing beauty that has no place in what is basically a summer sport now, dominated by more refined and systematic nations.

Independence for Scotland may or may not come about – and there were even some weird political nuances in the unveiling this week of the national teams's new away kit in the racing colours of the Earl of Rosebery, Old Etonian prime minister and a staunch opponent of Irish independence in his time, an act of subtextual football kit politics that might even have drawn yet another little gasp of joy No10 Downing Street.

But whichever way this ends up going, one thing is certain. We will always have football, an indissoluble shared Anglo-Scottish sporting history, and that brief glorious period when together we were kings.